1. Field of Invention
The present invention relates to projection monitors, displays, televisions, and other display systems. The invention is more particularly related to a kernel design used to impart an image into a light beam by separating the light beam into its component colors, individually modulating each component color, and then re-combining the modulated component colors into an output beam.
2. Discussion of Background
The function of a video projector and the prism assembly that is contained within it are explained with reference to FIG. 1. As shown, white light is generated by the light source. The light is collected, homogenized and formed into the proper shape by the condenser. UV and IR components are eliminated by filters. In this example, white light then enters a prism assembly where it is polarized and broken into red, green and blue beams. (Hence a “three channel”, quad type prism assembly.) These beams then follow different paths within the prism assembly such that each beam is directed to a specific reflective microdisplay. The microdisplay that interacts with the green beam contains the green content of the full color video image. It is similar for the blue and red microdisplays. On a pixel-by-pixel basis, the microdisplays modulate and then reflect the colored light beams. The prism assembly then recombines the modulated beams into a white light beam that contains a full color video image. The resultant white light beam then exits the prism assembly and enters the projection lens. Finally, the image-containing beam is projected onto a screen.
Several prism assembly configurations have been discussed in the technical and patent literatures. Some of these configurations are based on WDW (Wavelength Dependent Waveplates, a.k.a., wavelength or band specific retarders), in that they use one or more WDWs to manipulate light within the prism assembly.